Focusing device for cameras.



C. B. KNOTT.

FOCUSING DEVICE FOR CAMERAS.

APPLlcATmN man SEPT. n, ma`

1,232,333. mentali .my 3, 1917.

3 SHEETS-SHEET I.

C. B. KNOTT.

FOCUSING DEVICE FOR CAMERAS.

APPLICATION man 3591.14. 1913.

Patented July 3, 1917.

3 SHEETS-SHEET 2.

c. B. KNOTT.

FOCUSING DEVICE FUR CAMERAS.

APPLICATION FILED SEPT. 1l, 1913.

1,232,333, Patented July 3, 1917'.I

muh. O di! gua CLARENCE E. Knorr, CENEW Yonx, 1v.' Y.

roCUsING DEVICE'ECE. CAMERAS.

Specification of Letters :Paten-t,`

Application mea september 11, i313. sum1 No. 7s9,a`51.

To all whom t may concern:

Be it known that State of `New York, have invented certain new and useful Improvements in Focusing Devices for Cameras, of which the following is a specification.

My invention relates to an improvement'.

scale ,on the ground-glass screen in. reverse,

that is, what is on the left side will appear on the right, and what' is on the right will appear on the left side.

The lens of the camera will, in a measure,

take in and properly show as the eye does,

objects which are near and those which are at a distance, but to procure the best result and bring out that part of the view which it is desired to reproduce most prominently,

it is necessary to adjust the lens tothe vproper distance Afrom the plate or film on which the image is to be taken.

Nearly all cameras are provided with a scale showing the position at which the lens should be placed to properly focus the camera for objects which are at a greater or less distance therefrom. 'lhese scales are marked in divisions indicating feet or meters. For instance, the scale would have marked thereon the points at which the lens should be'positioned to properly focus the camera for an imagef, f6, 8, l0, l5, 25, and l0@ feet from the camera. This scale will vary in length from g to 1% of an inch more or less, which means that the lens can be adjusted within the scope of these measurements, and it will consequently be seen that if the distance from thecamera lens to the object to be photographed is not properlyV judged, there is a possibility that the may be badly out of focus.

As an example, if it is Idesiredv to photograph an object at eight feet from'the camera, and, by misjudgment of distance, the lens is set at fifteen on the scale, then an ob-4 ject at fteen feet from the camera would bein perfect focus, whereas the object which is intended to be brought out prominently I, CLARENCE B. KNo'r'r, a citizen of the UnitedStates, residing at New York city, in county-of New York and would be out of focus, and would consequently be indstinct-and blurred.

A further object is to provide a structure i with which 1t is not necessary to darken the` portion of the camera on which the image 1s thrown, as by placing a cloth over the hood in the one instance or looking into the hood in the other instance, and thus the operator can at all times see with the naked eye as well as in the finder just the position and attitude of the subject.

Yet another object is to provide a device which can be applied to any focusing camera now 1n use'without great alterations.

- This invention relates to certain novel features of construction and combinations of parts which will be hereinafter fully described and pointed out in the claims.

ln the accompanying drawings Figure 1 is a perspective view showing the camera with the focusing device in place thereon, 1

Fig. 2 is a view in front elevation, lFig. 3 is a view in rear elevation,l Fig. 4 is a top plan view,

Fig. 5 is an enlarged detail view of means for connecting -the device with moving parts of the camera, and,

Fig. 6 is a detail perspective view to illusthe the j trate a modified form of means for shifting vthe Ending mirror, and Fig. 7 is a detail view. showing the lens interposed between the reflectors. n

rlhe camera, to which the device is shown Vattached in the present instance, comprises a 'box A, lwhich has the front l hinged Patented J 'uly 3, 1917.

thereto 'toswing down. A track 2 is provided fon the front l, and the Carriage 3, in.

whichv the lens t is mounted, is constructed to slideon this track.

Ascale 5 is ,securedv on the carriage 3. Revolt/'ing' the thumb-wheel Y-6 which is connected on the shaft 7, the movable memberor base 3 on the carriage 3 is caused to :nove toward and from the box by an arrangement of gear and rack, or other suitable mechanism, (not shown) and the pointer 8 carried by the lens 1 indicates on the scale .the distance at which the lens is adjusted to procure the best results. The usual bellows rovided to'make a light-proof struc- 'lom'the lens' 4 to the box A, and the boximay be adapted for either plates or filmerf ture A frame ,9 lis carried by the ca 1riage.3, rl

vwhich l purpose to take advantage.

and is ,bent to be U-shaped and preferably to rise above and embrace the bellows B.

A shaft is mounted in the frame 9 at one sidev of the bellows, and by a. series of links 11, 12, and 13, as better shownv in Fig.

' 5, so that, as the thumb-wheel 6 is revolved to cause the movable member 3 ofthe car-v f riage to be adjusted in the one direction or theother, the shaft 10 is oscillated. A base member 14 lis removably connected uponthe frame 9, and an upright 15 is connected with this base member to be somewhat-'forward of the shaft 10.

A finder C is connected with the besef member 14 at one side of the upright member. This finder comprises a base 16,- on

which is supported a concaved lens 17. The" cured to the base 16 in front o the lens 17,

and by holding the camera with the -lens on the level of the eye, and lsighting therethrough with the cross-lines of the lens and ltn is not, however, possible in this manner to obtain any idea of the distance of the object from the lens. A mirror 19 is mounted on the upper end of the shaft 10.

` A nder D similar to the nder C is secured on a base 16 mounted on the upright member 15 with a lens 20 positioned to sight the mirror 19. The nder D has the lens provided with cross-lines and carried on the base 16', or in front of the lens is a sight 21. A mirror 22 is carried by the base on' that side of the lens away from thevsight 21. The mirror' 22 is held at such an angle that it reects the image shown through the lens 20,' and as this lenssightsrthe mirror 19 the 'image shown in the mirror 22 is theredection off-the view in front of the camera as caught in the' mirror 19. The mirror 19 has a screen23 pivoted thereto to be swung to such a position that it prevents the reiiectionv by themirror 22 'of objects directly in front thereof, and ,limits the reflections in that mirror to 'what is disclosed vin the lens 20.' l v As yset forth, the subject on vwhich ,the

, .focus is to be taken can be centered in the finder C, and in alike manner the nder D will centerv on what is reflected by the miriside or the other, and `it is this principle of The link 11 isisecured at its one end with the shaft 10 in such a manner that, as the y link is swung, the shaft is revolved or os- .'cillated in the one direction or the other.

This link is connectedat' its free end at 24 with the link 12, and link 12 is pivoted on member of the Acarriage 3. A slot 26 is provided in the '1ink'12, and a screw-bolt 27 passes through this'slot and into. a screw- Y threaded opening in one end of the link 13.

secured on the movable member 3 of the carriage.

From this it will be seenthatr as the movable member of the carriage is run out and in, the links through their connection cause theshat 10 to shuttle, andV thereby adjust the mirror 19 vangularly. A

By centering the subject in the nder C, and then turningthe thumb-wheel 6 to bring the mirror'19 to the proper angle to throw the relection in mirror 22 with the same subject centered,.the movable member 3 of thel carriage4 will be brought to a definite point, and the partsjare so arranged and adjusted that this point is the proper focus.

' The arrangement of links which l have described for changing the angle of the mirror 19 through the rotation vof the shaft 10 is particularly Well v.adapted for this function, as when the device .is to be applied to a camera having a greater or less focusing run, the point of pivot on 'the links 12 and 13.'can be changed to accommodate the condition. The manner in which this change would be made is better shown in Fig. 5. The screw-bolt'27 would be placed in one of the openings 28 of the lever 13 at a point nearer to the connection and the -moving member 3 of the carriage and the connection to the bracket 25l would be shifted to the required degree. l

ln the form illustrated in Fig. 6, a link arrangement for swinging the mirror 19 when this mirror is mounted on the box of the camera is disclosed. The shaft `10 is journaled inthe b oX and extends through the top thereof at a suitable point that'the mirror 19 removably mounted thereon is in proper position to reiiect the view to inder D, .which with inder C would be mounted on the top and side respectively ofthe'box A. The link 13 is-secured to the movable member 3 .of the carriage, link 12 has an .adjustable pivotal connection therewith through screw 27 and the link 12 is pivotedto the frontl `of the camera at 25. An

opening c is'formed through the shaft 10 and the rod a is'slidably received through the opening and -at its one end has a universal connection with the link 12. With this larrangement the universal joint and the sof tance farther fromthe'plate or film than.

with an object at a distance, and the run required when focusing under twenty-live feet increases greatly over that when focusing above twenty-five feet. This is admirably taken care of by the arrangement of the levers, as when the short end of lever 12 is swung past the point or pivot, the movement transmitted to the link 11 to throwT it aroundthe pivotal connection with the shaft 10 is materially decreased, and consequently the angle lof the mirror is shifted in a lessening degree, thus making it necessary to run the carriage out a greater distance to secure the angular adjustment of the mirror and the centering of the subject as reflected in the mirror. 22.

. The 'lens 20, finderk D, is hinged so thatit can be swung down from its position in the path of the reflection from the mirror 19 to the mirror 22, and while this lens is not in position the whole of the reflection as caught in the mirror 19 is not shown in mirror 22, yet that part which is shown is much increased `in size, and the details are more clearly defined for the purpose of focusing. Y

It is evident that the finders Gand D, and the mirror 19 can be made detachable, and the parts folded to such a position that they will fit into the box of the camera, or attach in other positions according as the camera may be used in a horizontal or vertical position in taking of a picture. Further, while the device has been described more as being an attachment for a camera, it can be constructed to be an essential part of the camera and to be built therein at the factory.

It is further evident that other changes might be made inthe form and arrangement of the parts, as, for instance, the means for causing the mirror 19 to be turned, and the other elements to adapt them to the structure and needs of the camera to which. the

device is to be applied, and hence I do not wish to limit myself .to the precise construction herein set forth, but

.I-Iaving fully. described my invention, what I claim as new and desire to secure by Letters Patent, is:-

1. A focusing device'for the purpose of determining the position 'of the lens of a camera so that it shall focus on the plate or film objects atvarying distances from the lens i one of which reflectors reflects the v iew or object in the field before the lens upon the other reflector, and a lens. proconsisting of fixed and `movable reflectors,

vided with centerin means' located between the two reflectors or centering the object before the lens in the path of 'reflection regardless of the adjustment of the movable reflector.

2. A focusing device for cameras, com- ,prising fixed and movable reflectors, and a lens located on a fixed path of reflection capable of centering in the Xed reflector any and every individual object separately along a line of vision, the rays of which coincide with the rays of the fixed path of reflection.

3. The Vcombination with a camera lensv and plate, of a movable and a fixed reflector capable lof receivingl and reflecting to the eye the entire portion of thev'iew or object destined to be brought to a focus on the film or plate, and means operable at the will of the operator interposed between said reflectors for centering the entire field as seen upon the fixed reflector thereupon.

4. The combination with a camera lens, of a movable reflector, and a stationary reflector in the line of vision between the eye and the object, and extensible means, applicable to cameras of different focal lengths, for operating the movable reflector, and

adapted to be actuated upon the movement j of the lens for causing the movable reflector to be operated for throwing a reflection of the eld before the camera on to the stationary reflector, and a screen located adj acent to the movable reflector for preventing reflections onto the stationary reflector from beyond the movable reflector.

5,. The combination, with a `camera lens, insuringits focus on the ground glass, the film or the plate, of a movable reflector, and a stationary reflector in the line of vision between the eye and the object, and extensible means, applicable to cameras of different focal lengths, for operating the lmovable res flector, and adapted to be actuated upon the movement of the lens for causing the movable reflector to be operated for throwing a reflection of the eld before the camera on the stationary reflector, and a screen located adjacent to the movable reflector for preventingl reflections onto the stationary reflector from beyond the vmovable reflector, and means located in the fixed path of reiiection capable of centering in the fixed. re-

flector any and every individual object along a line-of vision, separately, the-rays of which coincide with the rays of the fixed path of reflection, which is from the eye to the xed reflector and from the fixed' reflector to the moving reflector.

6. The combination with a camera lens and plate, of a movable and a fixed reflector capable of receiving and reecting to the eye the entire portioniof the view or object destined to be brought to a focus on the film or plate, and a hinged lens having centering means thereon interposed between said tion of the lield before the camera onto the stationary reiector, one' of the linkshaving a slot therein, and 'adjustable means on another link received in the slot,v whereby the links may be adjustedto cameras of diii'eren t focal length.

8.. The combination with a camera lens, of a fixed reflector,A a movable reflector for refleeting the view orield beforethe lens onto the fixed reiector, means'in the path of the reflection for centering` the reected view 0r field 'on the xed reflector to indicate when the lens is in focus, and a plurality of links:v ad]ustably connected together'and to the lens and movable reflectorv for causing themovement of the movable reflector on'the movement oft-he lens. one of the links be'- ing provided with a plurality of openings and another with a slot, and means for passing through an opening and the slot of the links',- whereby the'links'may be adjusted to cameras of different' focal length.

9. The combination with a 'camera lens, of a movableand stationary reector, a pluralv ity'of links connected together and to the movable rellectorand lens, whereby, uponthe movement of the lens', the movable re- Hector will be operated for throwing a re-.

llection of the field before the camera onto the stationary reiiector, one of the links being provided with an elongated slot, and another provided withv means for fo an adjustable connection. between the two links that they may be adapted to cameras of different focal lengths.

10. A focusing device for cameras, comprising fixed and movable reiectors, and a lens provided with centering means located v.between the .reflectors for 4locating and cen- 'tering inthe fixed reflectoi any individual part of or the complete object along a line vof vision, the rays ofwhich coincide with the rays of the fixed path of reiection. d 11. A focusing device forv cameras, comprising fixed and movable reflectors, and a.

vlens provided with centering means located between the reiiectorsffor locating and centering in the fixed reflector any lndividuall part of` or the complete object along a line of vision, the rays of which coincide with vthe rays of the xed path of reflection, and" `ascreen located with relation to the reecvvtors so thatall other than the desired light rays arel prevented from being reected in the 'fixed refiector. Y A In testimony whereof I ax, my signature. C5

in the presence of two'witnesses.-

` CLARENCE B. OTT. Witnesses: v A EDWARD A. EA'roN,'

Fnnnmrck BEGGERMAN. 

